Treatment of ethyl chloride catalyst



ennui-Autu 2,209,931

FuNlTEo STATES PATENT.

mmur fiz z'ifirnomonmn I I 'Alex 0. Key] and Robert D. Blue, Midland,Mich, assignors to The Dow Chemical Company, Midland, Mich, acorporation of ,Michigan No Drawing. Application September 1, 19 36,

' Serial No. 98,925

Claims. (01. 204-9) invention concerns amethod of preparing salt such asan aluminum halide can be added liquid catalytic media. to be employedin produewith beneficial results. The amount of such ing ethyl chlorideby the direct addition of hydroa ent neces ary is only about 0.01 percent by gen chloride to ethylene, and to'the treatment of weight o theganic liquid employed. If a 5 such media during their chlorinatedaliphatic hydrocarbon is employed as J5 According to one method forcarrying out'said the liquid base in preparing catalyst medium, aaddition reaction, a mixture of ethylene and small m u t' a a t u a r mii d hydrogen chloride in approximately equlmolecu-.- or a mineral acid,pable of pr mo in Ch m cal lar proportions is passed into a liquidcatalytic reaction between the aluminumanode and the 10 medium preparedwith aluminum chloride, mainchloro-hydrocarbon, can advantageously beused, 10

tained at a relatively low temperature, under subsince such procedurepermits the use; of lower stantially anhydrous conditions, and atapproxiv voltages to P the ame mount of current.

mately atmospheric pressure. A suitable medium I general, W pr f r touse a chlorinated alican be made by dissolving or suspending alumi-Phatie hydrocarbon in the Preparation of liquid num chloride in certainchlorinated aliphatic catalyst medium for the purposes indicated, and 15hydrocarbons. However, after a relatively short e ave fou dthet thepassage therethrou 0 period of use such liquid catalytic medium beanelectric current from an aluminum anode comes inactive to promote theaddition reaction effects not only an electrical resolving of alumiandmust be replaced, or fresh catalyst added num into the liquid but alsopromotes a chemical thereto. The intermittent addition of solidalureaction between the chloro-compound and the minum chloride to theliquid medium calls for the metal anode. The material from which thecathhandling of a very hygroscopic substance and ode is constructed is amatter of choice, carbon or thorough mixing to avoid localconcentrations of aluminum being suitable, but it is preferable to thecatalyst, and, in general, results in only relaselect a material whichis fairly acid-resistant.

g tively low yields of ethyl chloride per unit of The following exampleillustrates the practice catalyst used, i. e. only 5 to 40 parts byweight of of our invention in reactivating partially spent ethylchloride are obtained per part of catalyst. catalyst:

Among the objects of this invention are to pro- Ethyl chloride was P c dfor a time by convide (1) a convenient wa of preparing a .liquid tactinga gaseousm e f ethylene d hyd catalyst medium suitable for use incarrying out gen chloride in suitable p a a at t e rate of 30 theabove-described addition reaction, whereby 2.8 cubic feet per hour, witha catalyst solution relatively high yields of ethyl chloride can be p py d o g 10 grams of aluminum obtained per pound of catalyst employed;and, (2) chloride in 250 milliliters Of tetrachloroethane.

a method by which spent liquid catalyst medium The liquid catalyst'wasmaintained at a temperacan be at least partially reactivated and freshture of about 5 C. and the passage of the rea t 35 catalyst incorporatedtherewith in a convenient gases thereinto continued until only about 60per manner without the necessity of handling an cent of the ethylenepassing in contact therewith anhydrous metal halide.- The inventlon,then, was being reacted. 372 grams of ethyl chloride consists of themethod hereinafter fully described was obtained, amounting to a yield of37.2 grams 0 and particularly pointed out in the claims. of product pergram of aluminum chloride em- 40 Our method of preparing or treatingliquid pl y d. catalyst medium to be used in the reaction of Thepartially spent catalyst solution was then hydrogen chloride withethylene comprises the withdrawn into a glass container provided withstep of passing an electric current through said. an aluminum anode anda carbon cathode. 1.0 5 liquid while using an anode comprising aluminum.ampere current at 13 volts was passed through In the application of ourprocess to the reactithe solution between these electrodes for 15minvation and incorporation. of fresh catalyst in spent utes, andthereafter 0.2 amperes at 1 volt for 45 liquid medium initially formedwith aluminum m nut s t e t mp ra u f th s lut o b in chloride, or bythe process herein described, said maintained between 5 and 10 C. duringthe medium will serve as a conductor to pass current. electrolysis. Theeffective anode surface was '72 50 However, in the preparation of freshmedium, it is square inches, from which 2.1 grams of aluminum sometimesnecessary to add a substance to the metal was resolved into theelectrolyteorganie liquid comprising the reaction medium A mixture ofequimolecular proportions of which will lower its electrical resistance.For ethylene and hydrogen chloride was then con- I instance, arelatively small amount of a metal tacted with the activated catalyticliquid at the.

- mixtures medium suitable for use as a catalyst in preparpreparation.For example,in a tower rate of 2.8 cubic feet per hour,.until again onlyabout per cent of the ethylene was being reacted, whereby 594 grams ofethyl ,chloride was obtained without further treatment of said catalyticmedium. This represents a yield of 282 grams of ethyl chloride pergramoi' aluminum resolved into the spent solution from the aluminumanode.

Other compounds, such as ethylene chloride, 1.1.2-trichloroethane,tetrachioroethylene, acetylene tetrachloride, propylene chloride, etc.,or of the same, may be treated to yield a ing ethyl chloride fromhydrogen chloride and ethylene. Our method of catalyst preparation andactivation does not necessarily have to be carried out intermittently,but is applicable to continuous operating systems for ethyl chloridesystem wherein the liquid catalyst medium is continu ou'sly contactedwith a gaseous mixture of ethylene and hydrogen chloride, portions ofthe catalytic liquid, can be continuously circulated through anelectrolytic chamber outside the .reaction zone, in which chamberaluminum metal is continuously resolved from an aluminum anode into saidcirculating medium. If desired, the electrolytic activation of a liquidcatalytic medium may be accomplished by placing the electrodes directlyin the addition reaction zone. Each of the continuous passage andreactionof gaseous reactants during the activation of the liquidcatalyst and has the added advantage of not requiring a transfer of theentire body of reaction medium to a vessel outside of the reaction zonefor treatment, which would, of course, result in a cessation of ethylchloride formation.

Other modes of applyingthe principle of our invention may be employedinstead of those explained, change being made as regards the methodherein disclosed, provided the step or steps stated by any of thefollowing claims or the equivalent of such stated step or steps beemployed.

We therefore tinctly-claim' as our invention: 7

1. In chemical reactions wherein a liquid catalyst consistingessentially of aluminum chloride dissolved in a chlorinated aliphatichydrocarbon i employed, the step of periodically passing a the reactionby above modifications permits the particularly point out and disdirectelectric current from an in contact with the aluminum chloride solutionthrough said solution, whereby aluminum is dissolved i'rom the anode andthe. catalyst is reactivated;

2. In a method wherein ethyl chloride is produced by reacting hydrogenchloride with ethylene in the presence of a catalytically activeliquidconsisting essentially of aluminum chloride dissolved in a liquidchlorinated aliphatic hydrocarbon and the catalyst aluminum chloride isat least partially spent, the step of passing a direct electric currentfrom an aluminum anode in contact with the solution of partially spentcatalyst through said solution, thereby dissolving aluminum from theanode and reactivating the catalyst.

3. The process according to claim 2 wherein the chlorinated aliphatichydrocarbon solvent for the aluminum chloride is tetrachloroethane.

4. In a method of.making ethyl chloride by reacting hydrogen chloridewith ethylene in the presence tially of aluminum chloride dissolved in aliquid chlorinated aliphatic hydrocarbon, the step of regenerating thecatalyst without interrupting passing a direct electric current from analuminum anode in contact with the liquid catalyst through the latter,thereby dissolving aluminum i'rom the anode and reactivating thecatalyst.

5. In a method of preparing a catalyst medium to be used in reactinghydrogen chloride with ethylene, the steps which consist in adding to aliquid chlorinated aliphatic hydrocarbon a relatively small amount of anagent selected from the class consisting of metal halides, halogens, andmineral acids capable of promoting chemical reaction between aluminumand the chlorinated aliphatic hydrocarbon and reducing the electricalresistance of the latter, and subjecting the mixtially immersed in thechlorinated hydrocarbon whereby a substantial percentage of aluminumchloride is produced in a liquid catalyst medium in amount sumcient topromote the direct addition of hydrogen chloride to ethylene in amixture or these reactants in contact with such medium.

' ALEX C. KEYL.

ROBERT D. BLUE.

aluminum anode

